This invention relates generally to printers and facsimile machines, and more particularly to automatically feeding pages from a stack in a hardcopy device.
In printers and facsimile machines, it is very important to provide reliable and automatic feeding or "picking" of individual pages from an input stack into the paper path. It is equally important to provide a main drive roller for moving each page past a printing or scanning station to an output area.
Prior inexpensive printers typically used a single large diameter roller for picking the paper from a stack as well as for moving the paper past the printhead, as was used in previous DeskJet printers made by Hewlett-Packard Company. Many printers and facsimile machines often separate the paper picking function from the main drive roller function.
Some printers facilitate stack feeding by the use of springloaded trays which are usually removable for reloading of paper. Others printers such as the LaserJet Printers made by Hewlett-Packard Packard Company have complicated feeder/picking devices employing many parts in order to handle large quantity stacks of paper.
Most facsimile machines have a simplified picking scheme which provides very limited pressure at the leading edge of a several stacked pages placed in an automatic document feeder. This usually limits the number of pages in the stack to 5-10, with greater risk of misfeeds when putting more the a few pages in the stack.
Many printer devices have the capability of spacing apart successive pages which are picked from a stack, such as with timing devices, or the like.
There is a need to provide a more reliable, simplified low-cost integration of all of the aforementioned functions in order to assure satisfactory trouble-free operation of loading, picking, and moving pages along the paper path of printers and facsimile machines.